Machines are used to perform a wide variety of job functions, and may be mobile or stationary. For example, a typical machine is shown in FIG. 1 as a wheel loader, and is used for many earthworking and construction tasks. Other types of machines may include trucks, automobiles, marine craft, aircraft, dozers, graders, excavators, tractor trailers, trains, stationary electric power generators, and many others.
Typically, machines are powered, controlled and monitored using electric and electronic technology, which involves the use of electrical conductors to supply power and data to various components and locations. Traditionally, power and data are delivered on separate conductors. In machines such as this, an operator may control devices from a central location with data routed through independent data conductors dedicated to each device. Similarly, the power for any of these machines would normally originate at a power source and connect to a central location, typically a fuse block, for independent distribution on power conductors to locations throughout the machine.
In current systems, two or more conductors are required for each device. The total number of conductors required increases proportionally to the number of devices used by the machine, and the number is ever increasing. Future machines will require even more devices than do present machines. To minimize assembly problems on current machines, the conductors are bundled into complex and cumbersome wiring harnesses. With a larger number of conductors, the wiring harnesses become proportionally larger and proportionally harder to route around the machine. The cost and weight of the wiring harnesses also increases proportionally and the time to troubleshoot increases exponentially. For ease of assembly, harnesses use connectors. Large harnesses require large and expensive connectors. The addition of even one new device may require harness replacement or modification. Even when the desired conductors for service or modification are found, they may not be in a convenient location to perform the needed work to connect to the new device. Unfortunately, because of the ever-increasing percentage of machine functions being performed electronically, the problems will only continue to multiply.
Multiplexing has been used to try to reduce the number of individual conductors needed for electrical communication. Multiplexing is typically used to send multiple messages on a single pair of signal conductors to separate or independent receivers of electrical data. However, present day techniques of multiplexing groups of electrical functions are only partially solving system complexity problems and are merely creating additional layers of electrical hierarchy rather than reducing complexity of the electrical systems. Although these systems and methods may be adequate for the speed and bandwidth of some of today's electrical functions, speed and capacity become a significant problem as signal activity continues to increase.
Attempts have also been made to use a data communication system where data and power are routed over the same conductors. For example, it is known in motor vehicles to arrange functional devices to communicate with each other through supply conductors connected to the battery of the vehicle by means of a carrier current technique. One such example of a data communication system employing the use of carrier currents is disclosed by U.S. Pat. No. 5,745,027, to Malville. Malville, however, does not disclose features which would enable a combination of power and data delivery throughout a machine. For example, Malville does not disclose smart connectors that connect devices to a wire bus that are configured to communicate and work with other smart connectors. Malville also does not disclose techniques in which smart connectors are readily connected to the bus at any desired location during assembly, maintenance or upgrades. Furthermore, Malville does not disclose techniques for delivering large amounts of data over a combined power and data delivery bus that accounts for and compensates for data interference in harsh environments.
In U.S. Pat. No. 5,727,025, Maryanka discloses a system that allows for voice, music, video and data to be transmitted over direct current wires. The system of Maryanka, however, does not disclose the use of smart connectors in that the interface between devices and the direct current wires has no capability to interpret commands and control devices based on decision making. Maryanka's system also does not include techniques for smart connectors being readily connected at any desired locations on the direct current lines.